Advanced Telecommunications Computing Architecture

Advanced Telecommunications Computing Architecture (ATCA or AdvancedTCA) is the largest specification effort in the history of the PCI Industrial Computer Manufacturers Group (PICMG), with more than 100 companies participating. Known as AdvancedTCA, the official specification designation PICMG 3.x (see below) was ratified by the PICMG organization in December 2002. AdvancedTCA is targeted primarily to requirements for "carrier grade" communications equipment, but has recently expanded its reach into more ruggedized applications geared toward the military/aerospace industries as well. This series of specifications incorporates the latest trends in high speed interconnect technologies, next-generation processors, and improved Reliability, Availability and Serviceability (RAS).

An AdvancedTCA board (blade) is 280 mm deep and 322 mm high. The boards have a metal front panel and a metal cover on the bottom of the printed circuit board to limit electromagnetic interference and to limit the spread of fire. The locking injector-ejector handle (lever) actuates a microswitch to let the Intelligent Platform Management Controller (IPMC) know that an operator wants to remove a board, or that the board has just been installed, thus activating the hot-swap procedure. AdvancedTCA boards support the use of PCI Mezzanine Card (PMC) or Advanced Mezzanine Card (AMC) expansion mezzanines.

The shelf supports RTMs (Rear Transition Modules). RTMs plug into the back of the shelf in slot locations that match the front boards. The RTM and the front board are interconnected through a Zone-3 connector. The Zone-3 connector is not defined by the AdvancedTCA specification.

Each shelf slot is 30.48 mm wide. This allows for 14-board chassis to be installed in a 19-inch rack-mountable system and 16 boards in an ETSI rack-mountable system. A typical 14-slot system is 12 or 13 rack units high. The large AdvancedTCA shelves are targeted to the telecommunication market so the airflow goes in the front of the shelf, across the boards from bottom to top, and out the rear of the shelf. Smaller shelves that are used in enterprise applications typically have horizontal air flow.

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